架空输电线路覆冰监测光纤光栅拉力倾角传感器的研制

Development of Fiber Bragg Grating Tension & Tilt Sensor for Icing-monitoring of Overhead Transmission Lines

输电线路覆冰危害电网安全稳定运行。为解决现有输电线路覆冰在线监测系统需要现场电源,易受电磁干扰,不能分布式测量,使用寿命短等缺点,开发基于光纤布喇格光栅(fiber Bragg grating,FBG)传感技术的输电线路覆冰在线监测系统。基于光纤光栅传感技术,提出一种抗电磁干扰的光纤光栅拉力倾角一体化传感器。在该传感器中,通过设计双闭环U型槽结构形成了高精度抗偏载能力强的拉力传感单元;基于等强度梁易形变的特点研制了高分辨率小型化的倾角传感单元;采用增设不受力光纤光栅的方法解决了温度与应变交叉敏感问题。实验表明,所研制的光纤光栅传感器拉力倾角测量单元线性度高,传感器的灵敏度和分辨率较好,测量误差较小。基于该传感器的监测系统可实现准分布式测量,其测量范围可达100 km。

Icing on overhead transmission lines is a threat to the safety of power grid. To overcome the drawbacks of the existing icing-monitoring systems, such as the requirement for field power, the sensitivity to electromagnetic interference （EMI）, the unavailability of distribution measurement and a short lifespan, a novel on-line icing-monitoring system was constructed on the basis of the fiber Bragg grating （FBG） sensing technique, and a FBG tension-angle sensor was developed, which was immune to EMI. In the sensor, the tension-sensing section was designed as a closed-loop U-structure to improve the measurement accuracy of the tension-sensing section under eccentric load; a beam with uniform strength was used to achieve a high resolution angle measurement; an unforced FBG was placed in the sensor to solve the problem of cross-sensitivity between strain and temperature of FBG sensing. Results of tension and tilt angle experiment indicated that the sensor has the advantages of lower non-linear error, better sensitivity and higher resolution. The on-line icing-monitoring system based on the proposed sensor can achieve the quasi-distribution measurement for overhead transmission lines up to 100 km long.